Electric current responsive device



Oct. 5, 1937.

D. JOURNEAUX 2,094,986

ELECTRIC CURRENT RESPONSIVE DEVICE Fi1ed Aug. 27, 1930 2 Sheets-Sheet lInvenzor Didier Joumeaux Attorney Oct. 5, 1937. D. JOURNEAUX 2,094,936

ELECTRIC CURRENT RESPONSIVE DEVICE Filed Aug. 27, 1930 2 Sheets-Sheet 2Fig.4.

D/di Joumeaux By Patented Oct. 5, 1937 UNITED STATES PATENT OFFICEDidier Journaux, West Collingswood, N. J., assixnor, by mesneassignments, to Allis-Chalmers Manui'actuflnz Company,

Milwaukee,

Wis., a corporation or Delaware Application August 27,

17 Claims.

This invention relates to improvemnts in electro-magnetically operated,current responsive devices et the induction type and particulafly torelays actuated upon the occurrence of a variable current condition.

The usual electrical installation is provided with relays operating todisconnect the various portions of the installation upon the occurrenceof overioads which may not only disturb operatien but actuaily destroyportions of the installation. When several units of machines areavailable, the eflect of such overloads may be minimized or avoided oyproviding relays to connect the units in parallel to divide the overloadamong so manv units that the total overioad is so distributed as toconstitute less than the permissible maximum ioad on each unit. As soonas the overioad has disappeared, the same relays should disconnect thesuperfluous units to maintain the units at the maximum efliciency. Itis, however, necessary to use relays having a characteristicapproximately following the permissible load capacity of a machine forthe purpose of protecting the machine aainst overloads of long durationand of values lower than the setting of the overload relays used fordisconnecting the machine on short-circuits. Such relays should,however, have a long-time characteristic and their operatien should varynot only in function of the degree of overioad but also as a function ofthe load carried by the machine previously to the overload. Thus, forexample, if a machine is rated at 1000 kw. with an overioad guarantee of50% for hour following continuous operation at the rated load, the relayused for protecting the machine must have a characteristic such that ifthe machine has carried 1000 kw. continuously and the load is thenincreased to 1500 kw., th e relay should disconnect aiter hour operationof such increased load.

However, if the machine has been carrying only 500 kw. continuously andthe load is then increased to 1500 kw. the machine should be permittedto carry such increased load for more than the above pre-decermined timelimit following continuons capacity loading, Thermal overload relayshave been used heretoiore to provide the above protection againstoverloads of long duration and to open or close a switch element atcertain temperatures and thereby operate to connect or disconnect themachine. Thermal relays are also used in automatic substations for thepurpose of starting up additional machines when the total load exceedsthe capacity of the ma- 1930, Serial No. 478,035

chines in operation and to shut down the additiona1 machines when theload is again reduced.

The thermal relay, however, has a number of disadvantages which resultin inaccurate operation. One of such disadvantages is that the operationof the relay is dependent largely upon the ambient temperature, Thus ifthe relay is adjusted to close its contacts at a certain load and aftera certain time-delay for a low ambient temperature, the relay willdisconnect the machine at a lower current or after too short atime-delay if the ambient temperature is higher. Conversely, if therelay is adjusted for a higher ambient temperature, it will not functionsoon enough and the machine will be overloaded for a long time which mayresult in serions damage thereto. Another disadvantage of the thermalrelay is the difllculty of adjustment for the required serviceconditions due to the fact that it is difficult to duplicate thebi-metaliic or other thermostatic element used on account of variationsin the properties of the material and the workmanship of each element sothat each relay must be adjusted and calibrated individuaily whichprocess requires considerable time. Changes, during operation, in theproperties 015 the material used in the thermostatic element likewisecause the relay to lose its adjustment aiter having been in operationfor a certain length of time.

It is, therefore, among the objects of the present invention to providea current responsive electro-magnetic device in which the time requiredfor a movable element to take a predetermined position, in response to achange in the current impressed on the device, depends on the currentvalue preceding the change in current.

Another object of the invention is to provide a current responsiveelectro-magnetic device responsive to values of current impressedthereon, for relatively long periods of time.

Another object 01 the invention is to provide a time elementelectro-responsive device, the action of which is not dependent upon theambient temperature.

Another object of the invention is to provide a time elementelectro-responsive device in which an extensive range of movement of themoving element thereof insures a positive and accurate action of thedevice.

Another object of the invention is to provide a time elementelectro-responsive device which may be so proportioned as to have aninverse time characteristic or to have any other desired characteristic.

Another objeet of the invention is. to provide an electroresponsivedevice which may be used for indicating and for reeording continuously,a load demand and/or the maximum of a load demand.

Another objetzt of the invention is to provide an electro-responsivedevice for operating eontrol circuits in relation to an eleetrical loaddemand.

Anotlier objeet of the invention is to provide an electro-responsivedevice for disconnecting eleetric eurrent rectifiers of the vapor typefrom a load when the gas or vapor pressure in the rectifler becomesexcessive.

Objects and advantages, other than those above set forth, will beapparent from the following description when read in connection with theaceompanying drawings in Which Figure 1 is a diagrammatic illustrationof one embodiment 0;. the present invention partially showing themechanieal construction of the device schematicafly and the electricalconnections thereof, in diagram, partieularly,

Fig. 2 is a top eross-sectional view taken on the line AA cf Fig. 3 Witha portion of the dise broken away to show the meehanieal structure ofthe device in greater detail,

Fig. 3 is a front elevation showing eonstructional details of thedevice,

Fig. 4 is a dagrammatie illustration similar to that shown in Fig. 1,but showing a modification thereoi,

Fig. 5 is a partial top view showing a modified contact-makingarrangement,

Fig. 6 is a partial front elevation of the device showing the modifiedcontacting arrangement,

Fig. 7 is a top crcss-sectional view taken on the line BB cf Fig. 8 andillustrating one means whereby the operating eharacteristics of thedevice may be ehanged, and

Fig. 8 is a partial front elevation further illus trating the means forvarying the characteristics of the device shown in Fig. 7.

Reierring more particularly to the drawings by charaeters of reference,the reference numeral Il designates the core of an electro-magnet, the

coil 52 of which is connected with a source of constant alternatingvoltage designated at l3. The ocre il of the electro-magnet is formedwith the pole pieces M and l6, each of which is provided with a shadingring H and [8 respectively et suitable shape as will be set forthhereinafter. Pale piece M is movably mounted on a spindle l9 suitablysupported and extending through a portion of the core II. The spindle I9carries a contact-making arrangement for suitably controlling circuitswhich arrangement inciudes a drum 21 having eonductive portions orinserts 22 connected With the common line 23 of the circuits to becontrolled (only partially shown), the other lines of which are shown at24 and 26 as resilient arms ca'rrying rollers moving in contact with thesurface of the drum.

The mechanical details may be seen in Figs. 2 and 3 whieh-show that themovable pole piece [4 is rotated by a gear 21 mounted on the spindle l9and in mesh With gears 28 transmitting the rotation of a driving pinion29. The driving pinion is mounted on a suitably supported shaft 3lcarrying a disc 32 rotating between pole pieces [4 and [6 and which isalso under the influence of a second electromagnet ineluding a ocre 33having pole pieces 34 and 36 with shading rings 31 and 38 and a coil 39connected with 3. circuit of the apparatus to be controlled as at 4|. Apair of permanent magnets 42 and 43 are 59 a'rranged that the dise 32passes between the pales thereof and the magnets therefor act, as isWellknown, to obtain the proper speed characteristics of an inductiontype relay.

A leaf spring 44 is so'mounted on the core Il as to permit shading ringIl te engage therewith when the pole piece M has been rotatedsufliciently thereby again causing engagement et gear 21 with the gears28, whieh are disengaged during operation as will be expiainedhereinafter, when the disc 32 again rotates in conter-clockwisedirection. Pale piece 34 is rotatable by hand and is so adjusted as tobe able to retain the characteflstics of the relay for difierent valuesof rated eurrent in conductors 4l by maintainlng the torque cf magnet 33at its normal value for diierent eurrent ratings.

Assuming that the several portions of the entire relay structure are inthe position shown in Fig. 3 and that coil l2 is excited, the shadingrings H and 18 are then se loeated relative to each other that no torqueis produced on the dise 32. Oeil 39 being excited in proportion to theeurrent in conductors M, causes disc 32 to rotate in a clockwisedirection. But pole piece M 15 moved in counter-elockwise directionthrough the action of the gears 21, 28 and 29 thereby producing anincreasing torque on the dise tending to rotate the same in aeountercloekwise direction due to the changing relative positions of theshading rings H and [8 which torque causes the dise to slow down untilthe pole piece M reaches a position at which the torque exerted by theaction of coil 39 is exaetly counter-balanced by that of coil i 2. Anyincrease of eurrent in coil 39 repeats the above action until theequilibrium position is again reached and any decrease of eurrent willcause the reverse operation of that above to take place untilequilibrium is again reached. The pole piece M thus has a definiteequilibrium position for each value of current in the coil 39. The timerequired for pole piece I4 to rotate from one position to another inresponse to changes in eurrent in the source 4l depends not only on themagnitude of the current but also on the position of pole piece I4 priorto the current change and, therefore, on the preceding load eurrentpassing through the current coil 39. The time required, therefore, forpole piece M to reach a certain position will be shorter if thepreceding eurrent was high and longer if the preceding eurrent was low.The final position of pole piece M may be placed in any desired relationto the value of the current in conductors 4l merely by varying theshapes of pole pieces M, S and the shading rings I1, I8. Thus, thedisplacement cf pole piece M may be made proportional to the current inconductors 4! or to the square of the current, or to a more complicatedfunction dependent on the purpose in view. In the first instance, apointer l 5 afiixed to the drum 2l carried by pole piece M will be madeto move over a uniformly sub-divided scale 20 calibrated to valuesproportional to the short time eurrent demand in the conductors M andmeans, such as a second pointer 25 rotatably supported on a braeket 30and arranged to be actuated by a pusher 35, forming a part of pointer I5to register the largest displacement of the pointer [5 to indicate themaximum demand. As is usual in so-called demand meters, the response ofthe moving element is not instantaneous and the rate at which changes inourrent are followed may be adjusted, usually by var ying the positionof the drag magnets 42, 43.

As the moving element approaches the position of equilibrium the speedthereo1 decreases according to a law determined by the physicaldimensions of the pole pieces I4, I6 and the shading rings I1, [8. Thedisplacement of the moving element is therefore completed only if thecurrent is maintained in conductors 4l for a predetermined length oftime. The time necessary for the contacts to close may be inverselyproportional to such currents as is usual in an inverse time delayrelay, or may follow an arbitrary law also depending on the shapes 015the pole pieces I4, [S and of the shading rings I1, I8. If it is desiredto control the operation of an electric current rectifier, by means ofthe relay heretofore described, the position of the polepiece [4 may bemade to foilow the pressure in the rectifier tank which pressure shouldnot exceed a pre-determined value in operation of the rectifler. It willbe apparent that, if excessive current is maintained for a protractedlength of time in conductors 41, or if coil I2 accidentally becomesde-energized, disc 32 will tend to rotate pole piece l4 continuailywithout regard to the normal operating range thereof. Provision hasthereiore been made to prevent overtravel in that, it will be observedthat, a few of the teeth of gear 21 are removed and that the gear rim lsslit along a portion of its periphery adjacent the removed teeth andthat the free portion is bent downwardly in such a manner that the gear21 will disengage from the transmitting gear train 28. Gears 28 thenrotate without engaging gear 21 and any wear on the gear 21 will occuron the beht portion of such gear and wear of the pinion will coeur on aportion not normally in engagement with gear 21. Such rotation ishowever limited by the removal of portion of the piece of gear 21 asabove explained and pinion 28 then slips on the tooth of gear 21 withwhich it was last meshed. When normal conditions are restored, disc 32will first rotate in a counterclockwise direction to return pole piecei4 to a corresponding position and gears 21 and 28 will re-engage underthe action of the spring 44.

In the modified form of the system shown in Fig. 4, a current coil 39',connected in series with the coil 38, is arranged on the core Iladjacent the voltage coil l2 and in opposition therewith to reduce theaction 01 coil 12 as the current increases in conductors 4l therebyaccelerating the response of the disc to high current values in theconductors 4l and changing the characteristics of the relay.

A switching arrangement diifering from that previously illustrated andabove descrlbed is shown in top view and in aide elevation in Figures 5and 6 respectively. The drum 2| above described as attached to spindle18 of the pole piece I4 is here replaced by a rotatable armature 46. Thecore il et the electro-magnet is provided with a member 41 shunting aportion oi! the flux therethrough. A suitable tilting armature 48 onwhich a mercury switch tube 49 is mounted, is pivoted on the shuntarmature 41 in such position that the armature 46 may complete thecircuit from armature 48 to core Il. When armature 48 has beensufliciently rotated to be directly under armature 48, the magnetic fluxis forced to shlft in such manner as to flow through rotatable armature46 so that armature 48 tilts thereby opening or closing the controlcircuits dependent on the arrangement of the contacts in the switch 49.Suitable stops are provided to limit the movement of tilting armature 48thereby preventing interierence with the free movement ci rotatingarmature 48.

It is, of course, not essential that the movable pole piece be made as8. portion of the core il and pivoted thereon as above described, butsuch pole piece may be made as shown in Fig. 7 which illustrates amovable pole piece comprising a rectangular frame 5l iilled with ironlaminations 52. The trame o! pole piece 5l, 52 is however attached tothe spindle l8 suitably mounted on the core Il and carrying the drum 2!or other contacting arrangements as immediately above described. Thereare also many other ways of varying the operating characteristics ot theelectro-magnet il, l2 which will readily occur to one skilled inelectro-magnet construction and operation and which need not, therefore,be here described in detail; .it being suflicient to mention means suchas displacing the magnet relative to the disc, progressively shuntingthe air gap or the entire magnat, etc.

- It is evident from the above description that a structure according tothe present invention may be provided with as long a. time delay as maybe required by proper dimensioning 01 the electro-magnets and of thegears. It will also be seen that the operating time depends not only onthe load current but also on the position 01 movable pole piece l4 whichdepends on the previous load current carried by the relay. It will 'beseen irom the above that the present relay has all of the elementsnecessary to give it the characteristics of a thermal relay withouthaving the disadvantages inherent in such thermal relays. A relay of thecharacter herein described and to be hereinaiter claimed is not affectedby changing ambient temperatures because the operation thereof isindependent of temperature. The operation of the relay being based onmechanical and electro-magnetic principles similar to those employed inwatt-hour-meters and induction type relays, which are well-known to theart, the relay has a greater accuracy than a thermal relay. Thecharacteristics of the relay can be determined accurately beforeconstruction thereof thus facllitating correct setting for any requiredcondition and such characteristics or setting will not change with ageas is the case in thermal relays. The relay will therefore retain itsadjustments and its accuracy et operation.

Although but a few embodiments of the present invention have beenillustrited and described, it will be apparent to those skilled in theart that various changes and modifications may be made therein withoutdeparting from the spirit of the invention or from the scope of theappended claims.

The invention claimed is:

1. In a deviceof the character described, the combination of anelectro-magnet responsive to momentary load conditions of an electriccircuit, a disc mounted to be rotated by said electro-magnet, a secondelectro-magnet having an element adjustablc to position in dependenceupon the instant load conditions of said circuit in time in dependenceupon prior load conditions thereof, and means for controlling anelectric circuit, said disc and element cooperating to actuate saidcircuit controlling means.

2. In a device of the character described, the combination of anelectro-magnet responsive to the load conditions of an electric circuit,a disc mounted to be rotated by said electro-magnet, a secondelectro-magnet having a movable pole acustable to position in dependenceupon the instant load conditions of said circuit in time in dependenceupon the prior load conditions thereof, and a gear train eonneeting saiddise and the said movable pole, said gear train being formed to preventover-travel of said dise and te disengage once per revolution of themovable pole of said electro-magnet to prevent over-travel of said dise,and means for causing reengagement of said gear train.

3. In a device of. the eharaeter described, the

combination of an electro-magnet responsive to the load currentconditions of an electric circuit, 3. dise mounted to be rotated by saideleetromagnet, a second electro-magnet eooperating with the flrst saideleetromagnet to control the rate and extent of rotation of said dise independence upon prior and instant load conditions of said circuit, andmeans magnetieally operated by joint action of said dise and said secondeIeetro-magnet to actuate a switch element.

4. In a device of the character described, the eombination of anelectro-magnet responsive to the load current conditions of an electriccircuit, a dise mounted to be rotated by said eieetro-magnet, a secondeiectro-magnet, means ar;ranged on the said second electro-magnet forva'rying the rate of rotation of said dise by the flrst saideleetromagnet in dependence upon previous load conditions of saidcircuit, and means magnetically operated by joint action of said diseand the said second electro-magnet to efieet aetuation cf switchelements.

5. An eleetromagnetie responsive device comprising means exclusivelyresponsive to the momentary ioad conditions of an eleetric circuit, auelement adjusted to a position in dependence upon previoSioad conditionsof the eleetric circuit, constant gvoltage responsive means cooperatingwith the flrst said means to adjust said element to a diierent positionin dependenee upon the instant lad conditions of said circuit in time inde pendenee upon the previous and instant load conditions of theelectric circuit, and switching means controlling the electric circuit,a portion of the second said means being movable by said element andeooperating therewith to operate said switching means.

6. An electro-magneticaliy responsive device comprising anelectro-magnet exclusively responsive to the load conditions of anelectric circuit, a dise inductively adjusted t0 position in dependenceupon previous load conditions of the'eiectric circuit, a constantvoltage responsive eleetro-magnet cooperating with the flrst said magnetto adjust said dise to a diierent position dependent upon the instantload conditions of said circuit in time in dependence upon the previousand instant load conditions thereof, and switching means for controllingthe electric circuit, a portion of the second said eleetro-magnet beingmovable by said dise and cooperating therewith to operate said switchingmeans,

7. In an electromagneticaliy operated device, the eombination ofelectro-magnetic means responsive to the load conditions of an electriccircuit, a dise inductively adjusted to positions in dependence uponload conditions of the electric circuit prior to the load conditionsthereof at any given moment, constant voltage responsiveelectro-magnetic means cooperating with the flrst said means to adjustsaid dise from said position to a difierent position in dependence uponthe instant load conditions of said circuit in time in dependence uponthe previous and instant load conditions of the electric circuit, thelast said electro-magnetic means having a movable pole, and switchingmeans for controiling the electric circuit. the movable pole of thesecond said electro-magnetie means being movable by said dise andcooperating therewith to operate said switching means.

8. In an eleetro-magnetieafly operated device, an electro-magnetresponsive to the current conditions in an electric circuit, 9. disemounted to be rotated by said eleCtro-magnet, a second electro-magnethaving an element adjustable to 8. position in dependence upon currentconditions in said circuit prior to the current conditions thereof atany given moment, the said element being operable t0 vary the rate ofrotation of said dise by the flrst said eleetromagnet, and meanseonneeting said dise with the said element, the said means preventingover-travel of said element.

9. In an eleetro-magnetically operated device, an eleetro-maenetresponsive to the load conditions in aneleetric circuit, 8, dise mountedto be rotated by said eleetro-magnet, a second eleetromagnet having amovabl pole positioned by said dise responsive to load conditions in theeleetric circuit prior to the load conditions therein at any givenmoment, a gear train eonneeting said dise and said movable pole, saidgear train being formed to prevent ovr-travel of said movable pole, andmeans operable by said movable pole to indicate operation of the device.

10. In a device of the eharacter described, an element rotatable inclockwise and eounterclockwise directions, an eleetro-magnet forimparting a torque to said element to cause movement thereof inone ofsaid directions responsive to and in dependence upon a condition of aneleetrie circuit, a second eleetro-magnet for imparting a torque to saidelement to cause movement thereof in the other of said directions, andmeans aetuated responsive to movement of said element for varying thetorque imparted thercto by the said second eleetro-magnet.

11. In a device of the charaeter described, a dise rotatable in twodirections, an electro-magnet for imparting a torque to said dise tocause rotation thereof in one of said directions responsive to and independence upon a condition of an electric circuit, a secondelectro-magnet for imparting a torque to said dise te cause rotationthereof in the other of said direction, and means aetuated responsive torotation of said dise for varying the torque imparted thereto by thesaid second eleetro-magnet.

12. In a device of the eharacter described, a. dise rotatable in twodirections, an eIcetro-magnet operable to impart a torque to said diseto cause rotation thereof in one of said directions, a secondeleetro-magnet operable to impart a torque to said dise to causerotation thereof in the other said directions, and means aetuated bysaid dise for varying the torque imparted thereto by the said secondelectro-magnet.

13. In a device of the eharacter described, a dise rotatable in twodirections, an eleetro-magnet operable to impart a torque to said diset0 cause rotation thereof in one of said directions, a secondeleetro-magnet operable to impart a torque to said dise te causerotation thereof in the other said directions, and means aetuated bysaid dise operable to vary the rate of rotation thereof responsive tothe torque imparted thereto by the flrst said electro-magnet.

14. In a device of the character described, an

element rotatabIe in clockwise and counterwise directions,electromagnetic means variably energized responsive to and in dependenceon variations in conditions of an electric circuit for causing movementof said element in one of the said directions, electro-magneticallyactuated means for causing movement of said element in the other of saiddirections, and means actuated responsive to movement of said elementfor varying the action of the second said means thereon.

15. In a device of the character described, an clament rotatable inclockwise and counterclock wise directions, electromagnetic meansvariably energized responsive to and in dependence on variations in theconditions of an electric circuit for imparting to said element 2.torque proportional to the energization of said means, electromagneticmeans energized independently of said circuit for imparting a torque tosaid element tending to cause movement thereof in the other of saiddirections, and means actuated responsive to movement of said element ineither of said directions for varying the torque imparted threto by thesecond said means.

16. A demand indicator comprising in combination, a pair oftorque-producing mechanisms acting in opposition, one of said mechanismshaving a torque proportional to the momentary value of the quantity thedemahd for which is to be indicated and the other of said mechanismshaving an adjustable torque, a member acted upon jointly by saidtorque-producing mechanisms and movable in response to unbalance intheir actions, and movable means for adjusting the torque of said lattertorque-producing mechanism, so connected to said movable member as to bemoved thereby in a direction required to balance the action of saidtorque-producing mechanisms.

17. A demand indicator comprising in combination a pair oftorque-producing mechanisms acting in conjunction, one of saidmechanisms having an output proportional to the momentary value of aquantity, the demand for which is to be indicated, and the other of suchmechanisms having an adjustable output, an adjustable device acted uponjointly by said torque-producing mechanisms arranged to have itsadjustment varied when said mechanisms act thereon unequally, saiddevice being 50 connected to said adjustable torque-producing mechanismsas to vary the output thereof in the direction required to equalize theaction of said torque-producing mechanisms.

